Gamma-glutamylcysteine ethyl ester-induced up-regulation of glutathione protects neurons against Abeta(1-42)-mediated oxidative stress and neurotoxicity: implications for Alzheimer's disease.

Glutathione (GSH) is an important endogenous antioxidant found in millimolar concentrations in the brain. GSH levels have been shown to decrease with aging. Alzheimer's disease (AD) is a neurodegenerative disorder associated with aging and oxidative stress. Abeta(1-42) has been shown to induce oxidative stress and has been proposed to play a central role in the oxidative damage detected in AD brain. It has been shown that administration of gamma-glutamylcysteine ethyl ester (GCEE) increases cellular levels of GSH, circumventing the regulation of GSH biosynthesis by providing the limiting substrate. In this study, we evaluated the protective role of up-regulation of GSH by GCEE against the oxidative and neurotoxic effects of Abeta(1-42) in primary neuronal culture. Addition of GCEE to neurons led to an elevated mean cellular GSH level compared with untreated control. Inhibition of gamma-glutamylcysteine synthetase by buthionine sulfoximine (BSO) led to a 98% decrease in total cellular GSH compared with control, which was returned to control levels by addition of GCEE. Taken together, these results suggest that GCEE up-regulates cellular GSH levels which, in turn, protects neurons against protein oxidation, loss of mitochondrial function, and DNA fragmentation induced by Abeta(1-42). These results are consistent with the notion that up-regulation of GSH by GCEE may play a viable protective role in the oxidative and neurotoxicity induced by Abeta(1-42) in AD brain.

Boyd-Kimball D ，Sultana R ，Abdul HM ，Butterfield DA ... -  《JOURNAL OF NEUROSCIENCE RESEARCH》

Acetyl-L-carnitine-induced up-regulation of heat shock proteins protects cortical neurons against amyloid-beta peptide 1-42-mediated oxidative stress and neurotoxicity: implications for Alzheimer's disease.

Abdul HM ，Calabrese V ，Calvani M ，Butterfield DA ... -  《JOURNAL OF NEUROSCIENCE RESEARCH》

Ferulic acid ethyl ester protects neurons against amyloid beta- peptide(1-42)-induced oxidative stress and neurotoxicity: relationship to antioxidant activity.

Sultana R ，Ravagna A ，Mohmmad-Abdul H ，Calabrese V ，Butterfield DA ... -  《JOURNAL OF NEUROCHEMISTRY》

Elevation of brain glutathione by gamma-glutamylcysteine ethyl ester protects against peroxynitrite-induced oxidative stress.

Elevation of glutathione (GSH) has been recognized as an important method for modulating levels of reactive oxygen species (ROS) in the brain. We investigated the antioxidant properties of gamma-glu-cys-ethyl ester (GCEE) in vitro and its ability to increase GSH levels upon in vivo i.p. injection. GCEE displays antioxidant activity similar to GSH as assessed by various in vitro indices such as hydroxyl radical scavenging, dichlorofluorescein fluorescence (DCF), protein specific spin labeling, glutamine synthetase (GS) activity, and protein carbonyls. Intraperitoneal injection of GCEE to gerbils resulted in a 41% increase in brain total GSH levels in vivo as determined by the DTNB-GSH reductase recycling method. Gerbils injected with buthionine sulfoximine (BSO), an inhibitor of gamma-glutamylcysteine synthetase, had 40% less total brain glutathione. Gerbils injected with BSO followed by a GCEE injection had GSH levels similar to vehicle-injected controls, suggesting that GCEE upregulates GSH biosynthesis by providing gamma-glutamylcysteine and not cysteine. Cortical synaptosomes from GCEE-injected animals were less susceptible to peroxynitrite-induced oxidative damage as assessed by DCF fluorescence, protein-specific spin labeling, and GS activity. These experiments suggest that GCEE is effective in increasing brain GSH levels and may potentially play an important therapeutic role in attenuating oxidative stress in neurodegenerative diseases associated with oxidative stress such as Alzheimer disease.

Drake J ，Kanski J ，Varadarajan S ，Tsoras M ，Butterfield DA ... -  《JOURNAL OF NEUROSCIENCE RESEARCH》

Galantamine protects against oxidative stress induced by amyloid-beta peptide in cortical neurons.

Melo JB ，Sousa C ，Garção P ，Oliveira CR ，Agostinho P ... -  《-》